On Mon, Oct 29, 2018 at 10:24 AM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > On Mon 29-10-18 10:01:28, Alexander Duyck wrote: > > On Mon, 2018-10-29 at 17:35 +0100, Michal Hocko wrote: [..] > > > You are already doing per-page initialization so I fail to see a larger > > > unit to operate on. > > > > I have a patch that makes it so that we can work at a pageblock level > > since all of the variables with the exception of only the LRU and page > > address fields can be precomputed. Doing that is one of the ways I was > > able to reduce page init to 1/3 to 1/4 of the time it was taking > > otherwise in the case of deferred page init. > > You still have to call set_page_links for each page. But let's assume we > can do initialization per larger units. Nothing really prevent to hide > that into constructor as well. A constructor / indirect function call makes sense when there are multiple sub-classes of object initialization, on the table I only see 3 cases: typical hotplug, base ZONE_DEVICE, ZONE_DEVICE + HMM. I think we can look to move the HMM special casing out of line, then we're down to 2. Even at 3 cases we're better off open-coding than a constructor for such a low number of sub-cases to handle. I do not foresee more cases arriving, so I struggle to see what the constructor buys us in terms of code readability / maintainability?
